Any factor limiting the size of a population whose effect is not dependent on the number of individuals in the population, then such factor is called Density Independent Factor. It is things that the organisms have no control over.

Here in the given options, food shortage and disease are factors that are dependent on the number of population but Floods have no dependency.

Some examples of density independent factors are :: Earth quake, fires, volcanic eruptions, floods, and  all natural calamities.

Gene flow means migration of genes from one to another. This gene flow is caused by individuals moving into population.

tRNA abbreviated as A transfer RNA is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length, that serves as the physical link between the mRNA and the amino acid sequence of proteins.

True, Animals in the Taiga and Alpine Biomes hibernate during winter.

The animals in taiga and alpine biomes have several different kind of adaptations for survival. Some animals that hibernate during the winter take the help of camouflage to protect itself from enemies. During this period of hibernation, they slow their rate of metabolism and also use less amount of energy to survive the harsh weather.

Yes, we know that water is a universal solvent.

Water can moderate temperature because of the two properties: high-specific heat and the high heat of vaporization.

Water is a polar molecule that has a high level of polarity and attraction to ions and other polar molecules.

Hence, all the above given options are the properties of water.

Tether is a rope, chain, or the like, by which an animal is fastened to a fixed object so as to limit its range of movement.

Cord is rope like to tie. Hence, cord is most similar in meaning to tether.

In the novel entitled 1984 by George Orwell's, "War is Peace; Freedom is Slavery; Ignorance is Strength;" is one of the three slogans of the entity known only as “The Party,” English Socialist Party ("INGSOC" for short) of Oceania.

It means "describes the act of simultaneously accepting two mutually contradictory beliefs as correct, often in distinct social contexts."

The relative pronoun acts as the subject or object of the relative clause. It replaces words like she, he, him, her, they, them etc.

It is, therefore, wrong to repeat the pronoun in the relative clause.

Hence, the correct sentence is Shreya, who is my best friend, is a singer.